Creating variables larger than 8 bytes to pass between functions

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tybo1mos 2018-8-23

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https://ww2.mathworks.cn/matlabcentral/answers/415886-creating-variables-larger-than-8-bytes-to-pass-between-functions

评论： Walter Roberson 2018-8-23

I'm reading bytes from different places in a recorded data log file. Each byte that is read is are placed in an large double array (time, value1, value2 etc) which is then passed to another function. Each time I read a new byte I bit shift the previous value and add on the newly read value. Doing this i'm limited to using only 8 bytes for value1, value2 etc. Is there a way to create a variable that is say 16bytes in length that can be used for the bitshift. This 16byte variable would be placed in the array for a specific time value, and passed to another function to parse and decode.

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tybo1mos 2018-8-23

Still having some troubles with my original data being changed. I'm trying to take a hex value such as: 31A2B3C4D5E6F7A8 (decimal=3576618712069240744) example: a=fi(3576618712069240744,0,80,0); >> x.hex ans = '000031a2b3c4d5e6f800'

This does allow me to now do a bitshift and add more vlaues, however the right 3 bytes not coming out to the original value that I entered? Any idea what i'm doing wrong?

Walter Roberson 2018-8-23

在 MATLAB Online 中打开

a = fi(uint64(3576618712069240744),0,80,0)

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Answer 1

Walter Roberson 2018-8-23

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https://ww2.mathworks.cn/matlabcentral/answers/415886-creating-variables-larger-than-8-bytes-to-pass-between-functions#answer_333781

Yes, if you use the Fixed Point Toolbox, such as https://www.mathworks.com/help/fixedpoint/ref/fi.html . My memory is that the limit is 32767 bits, but I am not certain of that at all and I am having difficulty finding the reference. A limit of 1023 bits is also coming to mind.